Temperature variations typically have a significant impact on the locking process of a PLL circuit. During the operation of the PLL circuit, temperature changes (e.g., from −40° C. to 125° C. or vice-versa) may cause frequency drifts of the voltage controlled oscillator (VCO) of the PLL circuit. Typically, to compensation for those frequency drifts, the PLL circuit may move a VCO frequency control signal to bring the output frequency Fout of the VCO back to a required frequency (e.g., a reference frequency Fref×N). However, such a VCO frequency control signal may be outside the PLL circuit's charge pump's operation range, which may lead to a PLL lock failure.
Accordingly, it would be desirable and useful to provide an improved method and system for temperature variation compensation in a PLL.